Video on demand (VOD) service delivery involves the use of multiple real-time flows that originate when a consumer requests a specific video asset. The process flows are coordinated by a backend control system and are supported by a network of video servers, IP network elements and access control elements such as encryptors. Encryption of streaming content helps a content provider protect the content from piracy.
If a request is received from a consumer device for streaming content, the back office alerts a video streaming server to the request. The server then streams the requested content over the network to an edge device that is capable of encrypting the streaming data. The edge device may then initiate an encryption session for the content by requesting a set of control words (CWs) and a set of entitlement control messages (ECMs) from an ECM Generator (ECMG). A CW is a cryptographic key that is used to encrypt the data stream. An ECM is a message that transmits information for calculating the CW along with other digital rights management (DRM) information that is specific to the requested content. Once the edge device receives CWs/ECMs from the ECMG, it will begin to encrypt the requested content with the CWs. The edge device also embeds the ECM(s) into the transport stream and provides the encrypted content along with the embedded ECM(s) to the consumer device over the network. A decryptor within the consumer device will recover the CWs from embedded ECMs and use the CWs to decrypt the content, thereby producing clear, unencrypted content to be displayed for the consumer.
A problem with the current system is that the encryption session with an ECMG is not initiated until the arrival of the requested content stream at the edge device. The packets of the unencrypted video stream that are received at the edge device prior to arrival of the initial CW/ECM must be discarded as dictated by the service provider's policy. This may result in a poor or even unacceptable response time for video playback at the consumer device. These and other problems are addressed herein.